CN114374901B

CN114374901B - Communication method, device and optical network system for integrating QKD and optical access network

Info

Publication number: CN114374901B
Application number: CN202210023754.3A
Authority: CN
Inventors: 牛佳宁; 赵子岩; 翁晨; 李国春; 闫龙川; 孙咏梅
Original assignee: State Grid Information and Telecommunication Co Ltd
Current assignee: State Grid Information and Telecommunication Co Ltd
Priority date: 2022-01-10
Filing date: 2022-01-10
Publication date: 2024-04-19
Anticipated expiration: 2042-01-10
Also published as: CN114374901A

Abstract

The application discloses a communication method, a device and an optical network system for integrating QKD and an optical access network, relates to the field of quantum communication, can realize deployment of a QKD network, improves the safety of the optical network, and can provide more bandwidth resources. The optical network system includes: the system comprises an OLT and at least two groups of ONUs, wherein at least two QKD receiving devices, a first receiving device, a first transmitting device and a wavelength division multiplexer are arranged on the OLT, and each group of ONUs is provided with a QKD transmitting device, a second receiving device and a second transmitting device; at least two QKD receiving devices are connected with the QKD transmitting device through a wavelength division multiplexer, a first optical splitter and a second optical splitter, the first receiving device is connected with the second transmitting device through the wavelength division multiplexer, the first optical splitter and a third optical splitter, the first transmitting device is connected with the second receiving device through the first optical splitter and a fourth optical splitter, so that the ONU transmits signals in a wavelength division multiplexing mode, and the OLT transmits signals in a time division multiplexing mode.

Description

Communication method, device and optical network system for integrating QKD and optical access network

Technical Field

The present application relates to the field of quantum communications, and in particular, to a method and apparatus for integrating QKD with an optical access network, and an optical network system.

Background

With the progress of science and technology, new energy traveling, internet of things, intelligent home, intelligent power grid and the like develop very rapidly. Therefore, the number of access subscribers to the power communication network is rapidly increasing, which presents a great challenge to the existing power communication network. It is imperative to improve the regulation and adaptation of the distribution network. In addition, with the development of the construction of the power distribution network, information interaction is more frequent, network openness is enhanced due to the rising of emerging operation modes such as load aggregators, and the like, so that the safety threat of information communication is increased, and the advanced encryption technology is urgently needed to improve the information communication safety and ensure the safe and reliable operation of the power grid.

Currently, asymmetric encryption algorithms are widely used in internet communication services, and security is based on complexity of the algorithm. Subsequently, with the development of quantum computing technology, the future prospect of asymmetric encryption has proven unreliable. While quantum key distribution (quantum key distribution, QKD) has proven to be useful against the threat posed by quantum computing. As known from the law of quantum mechanics, in the QKD process, as long as an eavesdropper eavesdrops on information, both communication parties can discover the eavesdropper, so that the eavesdropper cannot eavesdrop on information without being discovered. That is, QKD and "one-time pad" techniques allow for the secure communication of information between two remote communications. In the early QKD deployment schemes, dedicated QKD networks were typically built by laying new optical fibers, bringing high time and monetary costs that are detrimental to the large-scale deployment applications of QKD.

Disclosure of Invention

The embodiment of the application provides a communication method, a device and an optical network system for integrating QKD with an optical access network, which can realize the integrated deployment of the QKD network and a passive optical access network, improve the safety of the optical network, reduce the deployment cost and provide more bandwidth resources.

In order to achieve the above purpose, the embodiment of the present application adopts the following technical scheme:

In a first aspect, there is provided an optical network system comprising: the system comprises an optical line terminal and at least two groups of optical network units, wherein the optical line terminal is provided with at least two quantum key distribution QKD receiving devices, a first receiving device, a first transmitting device and a wavelength division multiplexer, and each group of optical network units is provided with a QKD transmitting device, a second receiving device and a second transmitting device; wherein the QKD transmission apparatus disposed on any one group of optical network units corresponds to one QKD reception apparatus of at least two QKD reception apparatuses for transmitting a quantum signal to the one QKD reception apparatus, the one QKD reception apparatus for receiving the quantum signal transmitted by the QKD transmission apparatus disposed on the any one group of optical network units, the first transmission apparatus and the second transmission apparatus for transmitting classical signals, and the first reception apparatus and the second reception apparatus for receiving classical signals; the at least two QKD receiving devices are connected with the QKD transmitting device through the wavelength division multiplexer, the first optical splitter and the second optical splitter, the first receiving device is connected with the second transmitting device through the wavelength division multiplexer, the first optical splitter and the third optical splitter, the first transmitting device is connected with the second receiving device through the first optical splitter and the fourth optical splitter, the optical network unit transmits signals in a wavelength division multiplexing mode, and the optical line terminal transmits signals in a time division multiplexing mode.

Based on the optical network system provided in the first aspect, the optical network unit can send signals in a wavelength division multiplexing mode, and the optical line terminal can send signals in a time division multiplexing mode, so that the fusion deployment of the QKD network and the passive optical access network is realized, the quantum signals and the classical signals can share optical fiber resources, the safety of the optical network is improved, the deployment cost is reduced, and more bandwidth resources are provided.

In one possible implementation, the QKD transmission apparatus includes a transmission unit configured to transmit a quantum signal and a first quantum key pool configured to store a quantum key obtained by the QKD transmission apparatus; the QKD reception apparatus includes a reception unit configured to receive a quantum signal, and a second quantum key pool configured to store a quantum key received by the reception unit.

In one possible implementation, the at least two sets of optical network units are deployed with N second transmitting devices and M QKD transmitting devices, where the N second transmitting devices correspond to N classical channels, the M QKD transmitting devices correspond to M quantum channels, frequencies of the N classical channels are inversely related to transmit powers of the N second transmitting devices, any two of the N classical channels include R preparation quantum channels between classical channels adjacent in a frequency domain, and frequencies of the M quantum channels are included in (N-1) R preparation quantum channels. The inverse correlation of the frequencies of the N classical channels with the transmission powers of the N second transmitting devices may be understood as that the larger the frequency of the classical channel is, the smaller the transmission power of the second transmitting device corresponding to the classical channel is. That is, a smaller frequency may be configured for the classical channel corresponding to the second transmitting apparatus with a larger transmission power, and a larger frequency may be configured for the classical channel corresponding to the second transmitting apparatus with a smaller transmission power.

In one possible implementation, the M quantum channels are (N-1) R preliminary quantum channels, the quantum channels with the lowest noise power.

In a second aspect, a communication method of QKD and optical access network convergence is provided, and a communication apparatus performing the method may be an optical network unit; but also a module applied in an optical network unit, such as a chip or a chip system. The following description will take the execution body as an optical network unit as an example. The method comprises the following steps: transmitting a quantum signal to the optical line terminal in a wavelength division multiplexing mode through the second optical splitter and the first optical splitter, wherein the quantum signal is used for indicating a first key; and transmitting a first encrypted signal to the optical line terminal by adopting a wavelength division multiplexing mode through a third optical splitter and the first optical splitter, or receiving a second encrypted signal from the optical line terminal by adopting a time division multiplexing mode through the first optical splitter and the fourth optical splitter, wherein the first encrypted signal is obtained by encrypting a first classical signal through the first key, and the second encrypted signal is obtained by encrypting a second classical signal through the first key.

Based on the method provided in the second aspect, the optical network unit can distribute the quantum key to the optical line terminal and communicate with the optical line terminal through the quantum key, in the process, the quantum signal and the classical signal can share optical fiber resources, so that the communication safety is improved, the deployment cost of the QKD network is reduced, and more bandwidth resources are provided.

In one possible implementation, the optical network unit is configured with P second transmitting devices and 1 QKD transmitting device, where the P second transmitting devices correspond to P classical channels, the 1 QKD transmitting device corresponds to 1 quantum channel, the frequencies of the P classical channels are inversely related to the transmit powers of the P second transmitting devices, and any two of the P classical channels include R preparation quantum channels between adjacent classical channels in a frequency domain, where the quantum channels are (P-1) R preparation quantum channels, and the quantum channel has the lowest noise power.

In a third aspect, a communication method in which QKD and an optical access network are integrated is provided, and a communication apparatus performing the method may be an optical line terminal; but also a module applied in an optical line terminal, such as a chip or a chip system. The following describes an example in which the execution body is an optical line terminal. The method comprises the following steps: receiving a quantum signal from an optical network unit in a wavelength division multiplexing mode through a second optical splitter and a first optical splitter, wherein the quantum signal is used for indicating a first key; and receiving a first encrypted signal from the optical network unit by adopting a wavelength division multiplexing mode through the third optical splitter and the first optical splitter, or sending a second encrypted signal to the optical network unit by adopting a time division multiplexing mode through the first optical splitter and the fourth optical splitter, wherein the first encrypted signal is obtained by encrypting a first classical signal through the first key, and the second encrypted signal is obtained by encrypting a second classical signal through the first key.

Based on the method provided in the third aspect, the optical line terminal can receive the quantum key from the optical network unit and communicate with the optical network unit through the quantum key, in the process, the quantum signal and the classical signal can share optical fiber resources, so that the communication safety is improved, the deployment cost of the QKD network is reduced, and more bandwidth resources are provided.

In a fourth aspect, a communication device is provided for implementing the above method. The communication device may be an optical network unit as in the second aspect or a device comprising an optical network unit as described above; or the communication device may be the optical line terminal in the third aspect, or a device including the optical line terminal. The communication device comprises corresponding modules, units or means (means) for implementing the above method, where the modules, units or means may be implemented by hardware, software, or implemented by hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the functions described above.

In a fifth aspect, there is provided a communication apparatus comprising: a processor; the processor is configured to couple to the memory and to execute the method according to any of the above aspects in response to the instructions after reading the instructions in the memory. The communication device may be an optical network unit as in the second aspect or a device comprising an optical network unit as described above; or the communication device may be the optical line terminal in the third aspect, or a device including the optical line terminal.

With reference to the fifth aspect, in a possible implementation manner, the communication device further includes a memory, where the memory is used to store necessary program instructions and data.

With reference to the fifth aspect, in one possible implementation manner, the communication device is a chip or a chip system. Alternatively, when the communication device is a chip system, the communication device may be formed by a chip, or may include a chip and other discrete devices.

In a sixth aspect, there is provided a communication apparatus comprising: a processor and interface circuit; interface circuit for receiving computer program or instruction and transmitting to processor; the processor is configured to execute the computer program or instructions to cause the communication device to perform the method as described in any of the above aspects.

With reference to the sixth aspect, in one possible implementation manner, the communication device is a chip or a chip system. Alternatively, when the communication device is a chip system, the communication device may be formed by a chip, or may include a chip and other discrete devices.

In a seventh aspect, there is provided a computer readable storage medium having instructions stored therein which, when run on a computer, cause the computer to perform the method of any of the above aspects.

In an eighth aspect, there is provided a computer program product comprising instructions which, when run on a computer, cause the computer to perform the method of any of the above aspects.

A ninth aspect provides a communication system comprising an optical network unit for performing the method of the second aspect described above, and an optical line terminal for performing the method of the third aspect described above.

It should be noted that, on the premise that the schemes are not contradictory, the schemes in the above aspects may be combined.

Drawings

Fig. 1 is a schematic diagram of an optical network system architecture according to an embodiment of the present application;

fig. 2 is a schematic hardware structure of a communication device according to an embodiment of the present application;

fig. 3 is a schematic flow chart of a communication method of QKD and optical access network convergence provided in an embodiment of the present application;

fig. 4 is a schematic structural diagram of a communication device according to an embodiment of the present application.

Detailed Description

The following describes in detail the implementation of the embodiment of the present application with reference to the drawings.

The terminal communication access network part of the current distribution communication network mainly adopts an Ethernet Passive Optical Network (EPON) technology. However, with the development of a novel power system, mass terminal devices will be connected to a power distribution network, and meanwhile, large-bandwidth services such as monitoring video will be gradually increased, so that the conventional EPON technology based on time division multiplexing will be difficult to meet the increasing bandwidth demand. Meanwhile, in order to realize the integration of QKD and a power distribution communication network, the quantum signal and the power communication service are required to share resources, and the problem of resource shortage is further aggravated. Based on the above, the embodiment of the application provides a passive optical network (TIME AND WAVELENGTH division multiplexed passive optical network, TWDM-PON) based on time-division multiplexing, which can realize the deployment of a QKD network, improve the safety of the optical network, provide higher bandwidth and better support the resource sharing requirement of power distribution service and quantum signals growing in the future.

In the embodiment of the application, the QKD devices can be respectively deployed at the optical line terminal (optical LINE TERMINAL, OLT) side and the optical network unit (optical network unit, ONU) side, so that quantum signals and classical signals can be transmitted in a shared mode, and the problem of cost caused by independently deploying optical fibers for the QKD is avoided. For example, the QKD receiver may be disposed on the OLT side, the OKD transmitter may be disposed on the ONU side, or the QKD transmitter may be disposed on the OLT side, and the OKD receiver may be disposed on the ONU side. The embodiments of the present application will be described by taking an example in which a QKD receiving device is disposed on the OLT side, an OKD transmitting device is disposed on the ONU side, and the QKD transmitting device is disposed on the ONU side, similarly to the case in which the QKD receiving device is disposed on the OLT side, and the OKD transmitting device is disposed on the ONU side, and the description in the embodiments of the present application will not be repeated. The following describes an example of an optical network system 10 shown in fig. 1.

Fig. 1 is a schematic diagram of an optical network system 10 according to an embodiment of the present application. The optical network system 10 shown in fig. 1 includes: OLT 101, ONU group 106, and ONU group 107.OLT 101 is deployed on the substation (not shown in fig. 1) side, and ONU group 106 and ONU group 107 are connected to a plurality of distribution end-users (power distribution terminals, PDT) (not shown in fig. 1). PDT may be a feeder terminal unit (FEEDER TERMINAL unit, FTU), a remote terminal unit (remote terminal unit, RTU), etc.

Wherein OLT 101 has disposed thereon QKD receiver 1013, QKD receiver 1018, first transmitter 1011, at least one first receiver 1012, and wavelength division multiplexer 1016. Optionally, a circulator 1017 is also disposed on the OLT 101. QKD receiver 1013 is configured to receive a quantum signal. Optionally, QKD receive apparatus 1013 includes a receive unit 1014 and a first Quantum Key Pool (QKP) 1015. The receiving unit 1014 is configured to receive a quantum signal, and the first QKP 1015 is configured to store a received quantum key, so that in a case where it is difficult to meet an encrypted communication requirement through real-time key generation, the quantum key received in advance is stored. Similarly, QKD receive 1018 includes receive unit 1019 and first QKP. The receiving unit 1019 is configured to receive the quantum signal, and the first QKP is configured to store the received quantum key. The first transmitting means 1011 is arranged to transmit a non-quantum signal, also referred to as classical signal. The first receiving means 1012 is arranged to receive classical signals. Wavelength division multiplexer 1016 is used to effect demultiplexing of the upstream wavelength division multiplexed channels. In the embodiment of the application, the uplink direction refers to the direction from the ONU side to the OLT side, and the downlink direction refers to the direction from the OLT side to the ONU side. Circulator 1017 is used to transmit signals in a single direction.

The ONU group 106 has disposed thereon a QKD transmitting device 1065, at least one second transmitting device and at least one second receiving device, such as: the second transmitting device 1061, the second receiving device 1062, the second transmitting device 1063, and the second receiving device 1064, where the second transmitting device 1061 and the second receiving device 1062 may be regarded as one ONU and the second transmitting device 1063 and the second receiving device 1064 may be regarded as another ONU. Optionally, QKD transmission 1065 includes a transmission unit 1066 and a second QKP 1067. The transmitting unit 1066 is configured to transmit a quantum signal, and the second QKP 1067 is configured to store a quantum key obtained by the QKD transmitting apparatus 1065, for example, the second QKP 1067 is configured to store a quantum key generated by the QKD transmitting apparatus 1065, so that, in a case where it is difficult to satisfy an encrypted communication requirement through real-time key generation, a quantum key generated in advance is stored. At least one second transmitting means is arranged to transmit classical signals and at least one receiving means is arranged to receive classical signals.

On ONU group 107, QKD transmitting device 1075, at least one second transmitting device and at least one second receiving device are deployed, such as: the second transmitting apparatus 1071, the second receiving apparatus 1072, the second transmitting apparatus 1073 and the second receiving apparatus 1074, wherein the second transmitting apparatus 1071 and the second receiving apparatus 1072 can be regarded as one ONU, and the second transmitting apparatus 1073 and the second receiving apparatus 1074 can be regarded as another ONU. Optionally, QKD transmission 1075 includes a transmission unit 1076 and a second QKP 1077. The transmission unit 1076 is configured to transmit a quantum signal, and the second QKP 1077 is configured to store a quantum key obtained by the QKD transmission apparatus 1075, for example, the second QKP 1077 is configured to store a quantum key generated by the QKD transmission apparatus 1075, so that in a case where it is difficult to satisfy an encrypted communication requirement by real-time key generation, a quantum key generated in advance is stored. At least one second transmitting means is arranged to transmit classical signals and at least one receiving means is arranged to receive classical signals.

It is appreciated that QKD receiver 1013 or QKD receiver 1018 corresponds to one ONU group. For example, QKD receiver 1013 corresponds to ONU group 1065, and QKD transmitter 1065 is configured to transmit a quantum signal to QKD receiver 1013, and QKD receiver 1013 is configured to receive the quantum signal transmitted by QKD transmitter 1065. QKD receiver 1018 corresponds to ONU group 1075, and QKD transmitter 1075 is configured to transmit a quantum signal to QKD receiver 1018, and QKD receiver 1018 is configured to receive the quantum signal transmitted by QKD transmitter 1075.

It can be appreciated that when the number of second transmitting apparatuses and second receiving apparatuses deployed on the ONU group is greater than 1, the plurality of second transmitting apparatuses and the plurality of second receiving apparatuses can share one QKD transmitting apparatus, so that deployment cost of the QKD apparatus can be reduced, and practicality is improved. In other words, ONUs may be grouped, with each group sharing one QKD transmission apparatus, taking into account QKD deployment costs. Specifically, all ONUs may be divided into groups, with ONUs within a group sharing one QKD transmission apparatus, each ONU within a group acquiring a security key from the QKD transmission apparatus within that group.

Among them, QKD receiver 1013, QKD receiver 1018, and at least one first receiver 1012 are connected to wavelength division multiplexer 1016. The first transmitting device 1011 and the wavelength division multiplexer 1016 are connected to the circulator 1017. The circulator 1017 is coupled (e.g., via fiber optic connection) to a first optical splitter (splitter) 102. The first optical splitter 102 is connected (e.g., via optical fibers) to the second optical splitter 103, the third optical splitter 104, and the fourth optical splitter 105. Second optical splitter 103 is connected to QKD transmission apparatus 1065 and QKD transmission apparatus 1075. The third optical splitter 104 is connected to the second transmitting device 1061, the second transmitting device 1063, the second transmitting device 1071, and the second transmitting device 1073. The fourth optical splitter 105 is connected to the second receiving device 1062, the second receiving device 1064, the second receiving device 1072, and the second receiving device 1074. Thus, the ONU can transmit signals in a wavelength division multiplexing mode, and the OLT can transmit signals in a time division multiplexing mode. It can be appreciated that, the upstream classical channel is commonly used for transmitting distribution monitoring data and information data collected by an end user, and therefore, the bandwidth requirement is high, so that the upstream classical channel can work in a C-band and perform upstream transmission in a mode of wavelength division multiplexing (WAVELENGTH DIVISION MULTIPLEXED, WDM), and the downstream classical channel can work in an O-band and perform downstream transmission in a mode of time division multiplexing (time division multiplexed, TDM). The optical distribution network (optical distribution network, ODN) adopts a mode of combining a plurality of optical splitters to realize the coupling of uplink wavelength division multiplexing channels and the demultiplexing of downlink wavelength division multiplexing channels. It can be appreciated that, by using the time division multiplexing scheme of EPON technology in the downlink direction, the upgrade cost can be reduced, and smooth evolution can be realized. In the embodiment of the application, the optical splitter can also be a beam splitter.

It will be appreciated that the wavelength division multiplexer 1016 and circulator 1017 may be disposed not in the OLT 101 but in the ODN, without limitation.

Optionally, the optical network system 10 further comprises a plurality of PDTs (not shown in FIG. 1). The plurality of PDTs are respectively connected with the second transmitting device and the second receiving device in the ONU group, so that the PDTs can transmit signals to the OLT through the second transmitting device connected with the PDTs and can receive signals from the OLT through the second receiving device connected with the PDTs.

The optical network system 10 shown in fig. 1 is for example only and is not intended to limit the scope of the present application. It should be understood by those skilled in the art that in the specific implementation, the optical network system 10 may further include other devices, and the number of OLT, the first transmitting device deployed on the OLT side, the first receiving device, the QKD receiving device, the ONU group, the second transmitting device in each ONU group, the second receiving device, the QKD transmitting device, various optical splitters, or PDTs may also be determined according to specific needs, without limitation.

It can be appreciated that one challenge in fusing QKD with passive optical networks is the problem of crosstalk when quantum signals are co-fiber transmitted with classical signals. The quantum signal using single photon as carrier has very low power compared with classical signal, and the crosstalk of classical signal and the noise generated by nonlinear effect of optical fiber can greatly affect the performance of QKD system when transmitting with classical signal. The noise mainly includes in-band noise and out-of-band noise. In-band noise refers to noise generated by noise photons falling on a quantum channel, and out-of-band noise refers to noise generated by noise photons not falling on a quantum channel, which is a channel for transmitting quantum signals. The out-of-band noise mainly comprises channel crosstalk noise and the like, and the interference of the noise can be effectively restrained by adopting a multistage frequency domain filtering technology with high isolation at a QKD receiving end. In-band noise, such as four-wave mixing noise and spontaneous raman scattering noise generated during transmission, cannot be removed by a filtering technique, and has been regarded as a main interference factor in a co-fiber transmission system. Although classical signal power control, time filtering and other measures are adopted in the existing experiments to relieve in-band noise interference, the effect is still very limited. Therefore, reasonable planning is required for the quantum channel and the classical channel, so that noise photons generated by four-wave mixing and spontaneous raman scattering are prevented or reduced from falling on the quantum channel as much as possible, and the performance of quantum key distribution is improved.

It can be appreciated that the frequency of the quantum channel and the frequency of the classical channel are interleaved with each other in the frequency domain (i.e. the quantum channel is interleaved between the classical channels in the frequency domain) so as to effectively avoid that the four-wave mixing noise generated by the classical signal does not fall on the quantum channel. Therefore, the application can allocate frequencies for the quantum channel and the classical channel in a way that the quantum channel and the classical channel are mutually interweaved in the frequency domain so as to reduce four-wave mixing noise. For raman scattering noise, the noise spectrum is distributed in a V shape in the range of about 20nm of the pump light, and the low frequency component (stokes component) in the noise is larger than the high frequency component (anti-stokes component), so if the frequency of the high-power classical channel is located at the low frequency side, the noise interference suffered by the quantum channel comes from the high frequency component, and the noise interference can be reduced. Therefore, in the embodiment of the application, a lower frequency can be configured for a classical channel with higher transmission power, and a higher frequency can be configured for a classical channel with lower transmission power, so as to reduce raman scattering noise.

In one possible implementation, if N second transmitting devices and M QKD transmitting devices are deployed on at least two groups of ONUs, where the N second transmitting devices correspond to N classical channels, and the M QKD transmitting devices correspond to M quantum channels, the frequencies of the N classical channels are inversely related to the transmit powers of the N second transmitting devices. Among the N classical channels, any two adjacent classical channels in the frequency domain include R preliminary quantum channels (the R value depends on the minimum channel spacing supported by the wavelength division multiplexing device, each of the R preliminary quantum channels has a frequency smaller than the minimum frequency of the adjacent two classical channels and greater than the maximum frequency of the adjacent two classical channels), and the frequency of the M quantum channels is included in the frequency of (N-1) R preliminary quantum channels. Where N and M are positive integers, N is greater than or equal to M, and the frequencies of the N classical channels, the inverse correlation with the transmission powers of the N second transmitting apparatuses may be understood as the greater the frequency of the classical channel, the smaller the transmission power of the second transmitting apparatus corresponding to the classical channel. That is, a smaller frequency may be configured for the classical channel corresponding to the second transmitting apparatus with a larger transmission power, and a larger frequency may be configured for the classical channel corresponding to the second transmitting apparatus with a smaller transmission power. The transmission power of the N second transmitting apparatuses may be the same or different. Therefore, the interference of Raman scattering noise and four-wave mixing noise can be effectively reduced, and the quantum key distribution performance is improved.

Further, the M quantum channels are (N-1) quantum channels with the lowest noise power among the R preliminary quantum channels. Thus, the channel with the lowest noise power can be used as a quantum channel, so that the quantum key distribution performance is further improved.

For example, taking the optical network system 10 shown in fig. 1 as an example, if 2 second transmission devices are disposed on the ONU 106, that is, the second transmission device 1061 and the second transmission device 1063, and 2 second transmission devices are disposed on the ONU 107, that is, the second transmission device 1071 and the second transmission device 1073, respectively, where the transmission power of the second transmission device 1061 < the transmission power of the second transmission device 1063 < the transmission power of the second transmission device 1073, then the frequency of the classical channel corresponding to the second transmission device 1061 > the frequency of the classical channel corresponding to the second transmission device 1063 > the frequency of the classical channel corresponding to the second transmission device 1071 > the frequency of the classical channel corresponding to the second transmission device 1073, and/or the frequency 2 of the quantum channel corresponding to the QKD transmission device 1075 may be located between the frequency of the classical channel corresponding to the second transmission device 1061 and the frequency of the classical channel corresponding to the second transmission device 1063, or between the frequency of the classical channel corresponding to the second transmission device 1063 and the classical channel corresponding to the second transmission device 1071, or between the frequency of the classical channel corresponding to the second transmission device 1071 and the classical channel corresponding to the second transmission device 1071. Alternatively, if, among classical channels 1 and 2 corresponding to the second transmission device 1061 and 1063, classical channel 3 and 4 corresponding to the second transmission device 1071 and 1073, 2 preliminary quantum channels are included between any two adjacent classical channels in the frequency domain, for example, preliminary quantum channel 1 and preliminary quantum channel 2 are included between classical channel 1 and classical channel 2, preliminary quantum channel 3 and preliminary quantum channel 4 are included between classical channel 2 and classical channel 3, and preliminary quantum channel 5 and preliminary quantum channel 6 are included between classical channel 3 and classical channel 4, then frequency 1 of the quantum channel corresponding to the QKD transmission device 1065 may be the frequency of any one of the preliminary quantum channels 1 to 6, and frequency 2 of the quantum channel corresponding to the QKD transmission device 1075 may be the frequency of any one of the preliminary quantum channels 1 to 6. Further, based on the raman scattering noise power calculation formula in the QKD system noise source analysis theory, the noise level of each of the preliminary quantum channels can be obtained, and the 2 channels with the lowest noise power are selected as the final quantum channels, that is, the quantum channels corresponding to the QKD transmission device 1065 and the quantum channels corresponding to the QKD transmission device 1075 are the 2 quantum channels with the lowest noise power, out of the 6 preliminary quantum channels.

Alternatively, each device (such as OLT or ONU) in fig. 1 in the embodiment of the present application may also be referred to as a communication apparatus, which may be a general-purpose device or a special-purpose device, which is not specifically limited in the embodiment of the present application.

Optionally, the relevant functions of each device in fig. 1 in the embodiment of the present application may be implemented by one device, or may be implemented by multiple devices together, or may be implemented by one or more functional modules in one device, which is not specifically limited in the embodiment of the present application. It will be appreciated that the functions described above may be either network elements in a hardware device, or software functions running on dedicated hardware, or a combination of hardware and software, or virtualized functions instantiated on a platform (e.g., a cloud platform).

In a specific implementation, each device shown in fig. 1 may adopt the constituent structure shown in fig. 2, or include the components shown in fig. 2. Fig. 2 is a schematic diagram of a hardware configuration of a communication device applicable to an embodiment of the present application. The communication device 20 comprises at least one processor 201 and at least one communication interface 204 for implementing the method provided by the embodiment of the application. The communication device 20 may also include a communication line 202 and a memory 203.

The processor 201 may be a general purpose central processing unit (central processing unit, CPU), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits for controlling the execution of the program of the present application.

Communication line 202 may include a pathway to transfer information between the aforementioned components, such as a bus.

Communication interface 204 for communicating with other devices or communication networks. The communication interface 204 may be any transceiver-like device such as an ethernet interface, a radio access network (radio access network, RAN) interface, a wireless local area network (wireless local area networks, WLAN) interface, a transceiver, a pin, a bus, or transceiver circuitry, etc.

The memory 203 may be, but is not limited to, a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (random access memory, RAM) or other type of dynamic storage device that can store information and instructions, or an electrically erasable programmable read-only memory (ELECTRICALLY ERASABLE PROGRAMMABLE READ-only memory, EEPROM), a compact disc read-only memory (compact disc read-only memory) or other optical disc storage, a compact disc storage (including compact disc, laser disc, optical disc, digital versatile disc, blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. The memory may be self-contained and coupled to the processor 201 via communication line 202. Memory 203 may also be integrated with processor 201. The memory provided by embodiments of the present application may generally have non-volatility.

The memory 203 is configured to store computer-executable instructions related to executing the solution provided by the embodiment of the present application, and is controlled by the processor 201 to execute the instructions. The processor 201 is configured to execute computer-executable instructions stored in the memory 203, thereby implementing the method provided by the embodiment of the present application. Alternatively, in the embodiment of the present application, the processor 201 may perform the functions related to the processing in the method provided in the embodiment of the present application, where the communication interface 204 is responsible for communicating with other devices or communication networks, and the embodiment of the present application is not limited in detail.

Alternatively, the computer-executable instructions in the embodiments of the present application may be referred to as application program codes, which are not particularly limited in the embodiments of the present application.

The coupling in the embodiments of the present application is an indirect coupling or communication connection between devices, units, or modules, which may be in electrical, mechanical, or other forms for information interaction between the devices, units, or modules.

As one example, processor 201 may include one or more CPUs, such as CPU0 and CPU1 in fig. 2.

As one example, the communication device 20 may include a plurality of processors, such as the processor 201 and the processor 205 in fig. 2. Each of these processors may be a single-core (single-CPU) processor or may be a multi-core (multi-CPU) processor. A processor herein may refer to one or more devices, circuits, and/or processing cores for processing data (e.g., computer program instructions).

It will be appreciated that the constituent structures shown in fig. 2 do not constitute a limitation of the communication device, and that the communication device may include more or less components than those shown in fig. 2, or may combine certain components, or may be arranged in different components.

The method provided by the embodiment of the application will be described below with reference to the accompanying drawings. Each network element in the following embodiments may be provided with the components shown in fig. 2, which are not described in detail.

It should be noted that, in the following embodiments of the present application, a name of a message between each network element or a name of each parameter in a message is only an example, and in specific implementations, other names may also be used, which is not limited in particular by the embodiments of the present application.

It should be noted that, in the embodiment of the present application, "/" may indicate that the related objects are in an "or" relationship, for example, a/B may indicate a or B; "and/or" may be used to describe that there are three relationships associated with an object, e.g., a and/or B, which may represent: there are three cases, a alone, a and B together, and B alone, wherein a, B may be singular or plural. Furthermore, expressions similar to "at least one of A, B and C" or "at least one of A, B or C" are generally used to denote any one of the following: a alone; b alone; c alone; both A and B are present; both A and C are present; b and C are present simultaneously; a, B and C are present simultaneously. The above is an alternative entry for the item exemplified by A, B and C together with the three elements, the meaning of which can be obtained according to the rules described above when there are more elements in the expression.

In order to facilitate description of the technical solution of the embodiments of the present application, in the embodiments of the present application, the words "first", "second", etc. may be used to distinguish between technical features that are the same or similar in function. The terms "first," "second," and the like do not necessarily denote any order of quantity or order of execution, nor do the terms "first," "second," and the like. In embodiments of the application, the words "exemplary" or "such as" are used to mean examples, illustrations, or descriptions, and any embodiment or design described as "exemplary" or "such as" should not be construed as preferred or advantageous over other embodiments or designs. The use of the word "exemplary" or "such as" is intended to present the relevant concepts in a concrete fashion to facilitate understanding.

It is appreciated that reference throughout this specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, various embodiments are not necessarily referring to the same embodiments throughout the specification. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. It should be understood that, in various embodiments of the present application, the sequence number of each process does not mean that the execution sequence of each process should be determined by the function and the internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

It is to be understood that, in the present application, "when …", "if" and "if" all mean that the corresponding process is performed under some objective condition, and are not limited in time, nor do it require that there be any judgment in the implementation, nor are other limitations meant to be implied.

It can be appreciated that some optional features of the embodiments of the present application may be implemented independently in some scenarios, independent of other features, such as the scheme on which they are currently based, to solve corresponding technical problems, achieve corresponding effects, or may be combined with other features according to requirements in some scenarios. Accordingly, the device provided in the embodiment of the present application may also implement these features or functions accordingly, which will not be described herein.

It will be appreciated that the same steps or technical features having the same function in the embodiments of the present application may be referred to and referred to in different embodiments.

It is to be understood that, in the embodiments of the present application, the OLT and/or the ONU may perform some or all of the steps in the embodiments of the present application, these steps are only examples, and the embodiments of the present application may also perform other steps or variations of the steps. Furthermore, the various steps may be performed in a different order presented in accordance with embodiments of the application, and it is possible that not all of the steps in an embodiment of the application may be performed.

As shown in fig. 3, in an embodiment of the present application, a communication method of QKD and optical access network convergence may be applied to the optical network system 10, where the communication method of QKD and optical access network convergence may include the following steps:

s301: the ONU transmits quantum signals to the OLT through the second optical splitter and the first optical splitter in a wavelength division multiplexing mode. Correspondingly, the OLT receives the quantum signal from the ONU by using a wavelength division multiplexing manner through the second optical splitter and the first optical splitter.

The ONU may be an ONU in any one of the ONU groups in the optical network system 10 shown in fig. 1, and the OLT is the OLT 101 in the optical network system 10 shown in fig. 1. The quantum signal may be used to indicate the first key. The first key may be used to encrypt signals between the ONU and the OLT.

Illustratively, taking optical network system 10 shown in fig. 1 as an example, QKD transmission apparatus 106 can transmit quantum signals to QKD reception apparatus 1013 via second optical splitter 103, first optical splitter 102, circulator 1017, and wavelength division multiplexer 1016 in a wavelength division multiplexed manner. Accordingly, QKD receiver 1013 receives the quantum signals from QKD transmitter 106 via second optical splitter 103, first optical splitter 102, circulator 1017, and wavelength division multiplexer 1016 in a wavelength division multiplexed manner.

In one possible implementation manner, the ONU is configured with P second transmitting devices and 1 QKD transmitting device, where the P second transmitting devices correspond to P classical channels, the 1 QKD transmitting device corresponds to 1 quantum channel, the frequencies of the P classical channels are inversely related to the transmitting power of the P second transmitting devices, and any two of the P classical channels include R preparation quantum channels between adjacent classical channels in the frequency domain, and the 1 quantum channels are (P-1) ×r preparation quantum channels, where the noise power is the lowest quantum channel. For specific description, reference may be made to the corresponding description in the description of the optical network system, which is not repeated herein.

S302: and the ONU and the OLT are communicated by encryption through a first key.

In one possible implementation manner, the ONU sends the first encrypted signal to the OLT through the third optical splitter and the first optical splitter in a wavelength division multiplexing manner, or receives the second encrypted signal from the OLT through the first optical splitter and the fourth optical splitter in a time division multiplexing manner. Correspondingly, the OLT receives the first encrypted signal from the ONU through the third optical splitter and the first optical splitter in a wavelength division multiplexing manner, or sends the second encrypted signal to the ONU through the first optical splitter and the fourth optical splitter in a time division multiplexing manner.

The first encrypted signal is obtained by encrypting the first classical signal through a first key, and the second encrypted signal is obtained by encrypting the second classical signal through the first key.

Illustratively, taking the optical network system 10 shown in fig. 1 as an example, the second transmitting device 1061 may transmit the first encrypted signal to the first receiving device 1012 in a wavelength division multiplexing manner through the third optical splitter 104, the first optical splitter 102, the circulator 1017, and the wavelength division multiplexer 1016. Accordingly, the first receiving apparatus 1012 receives the first encrypted signal from the second transmitting apparatus 1061 through the third optical splitter 104, the first optical splitter 102, the circulator 1017, and the wavelength division multiplexer 1016 in a wavelength division multiplexing manner. Or the first transmitting device 1011 may transmit the second encrypted signal to the second receiving device 1064 through the circulator 1017, the first optical splitter 102, and the fourth optical splitter 105 in a time division multiplexing manner. Accordingly, the second receiving apparatus 1064 receives the second encrypted signal from the first transmitting apparatus 1011 through the circulator 1017, the first optical splitter 102, and the fourth optical splitter 105 in a time division multiplexing manner.

The actions of the ONU or OLT in S301 to S302 may be performed by the processor 201 in the communication device 20 shown in fig. 2 calling the application code stored in the memory 203, which is not limited in any way by the embodiment of the present application.

The above-mentioned embodiments of the present application may be combined without limitation, where the schemes are not contradictory.

The scheme provided by the embodiment of the application is mainly introduced from the interaction point of the devices. Correspondingly, the embodiment of the application also provides a communication device, which can be the ONU in the embodiment of the method, or a device containing the ONU, or a component applicable to the ONU; or the communication device may be the OLT in the above method embodiment, or a device comprising the OLT, or a component that may be used in the OLT. It is understood that, in order to implement the above functions, the ONU or OLT includes a hardware structure and/or a software module that perform each function. Those of skill in the art will readily appreciate that the present application may be implemented in hardware or a combination of hardware and computer software, as a unit and algorithm operations described in connection with the embodiments disclosed herein. Whether a function is implemented as hardware or computer software driven hardware depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

The embodiment of the application can divide the functional modules of the ONU or the OLT according to the method example, for example, each functional module can be divided corresponding to each function, and two or more functions can be integrated in one processing module. The integrated modules may be implemented in hardware or in software functional modules. It should be noted that, in the embodiment of the present application, the division of the modules is schematic, which is merely a logic function division, and other division manners may be implemented in actual implementation.

For example, fig. 4 shows a schematic configuration of a communication device 40 in the case of dividing the respective functional modules in an integrated manner. The communication device 40 comprises a transceiver module 401. The transceiver module 401, which may also be referred to as a transceiver unit, is used to implement a transceiver function, and may be, for example, a transceiver circuit, a transceiver, or a communication interface.

In some embodiments, the communication device 40 may also include a memory module (not shown in fig. 4) for storing program instructions and data.

Illustratively, the communication device 40 is configured to implement the functionality of an ONU. The communication device 40 is for example an ONU as described in the embodiment shown in fig. 3.

The transceiver module 401 is configured to send, by using a second optical splitter and a first optical splitter, a quantum signal to an optical line terminal in a wavelength division multiplexing manner, where the quantum signal is used to indicate a first key; the transceiver module 401 is further configured to send, by using a third optical splitter and a first optical splitter, a first encrypted signal to the optical line terminal in a wavelength division multiplexing manner, or receive, by using a first optical splitter and a fourth optical splitter, a second encrypted signal from the optical line terminal in a time division multiplexing manner, where the first encrypted signal is obtained by encrypting a first classical signal with a first key, and the second encrypted signal is obtained by encrypting a second classical signal with the first key.

In one possible implementation, the communication device 40 is configured with P second transmitting devices and 1 QKD transmitting device, where the P second transmitting devices correspond to P classical channels, the 1 QKD transmitting device corresponds to 1 quantum channel, the frequencies of the P classical channels are inversely related to the transmit powers of the P second transmitting devices, and any two of the P classical channels include R preparation quantum channels between adjacent classical channels in the frequency domain, where the quantum channels are (P-1) R preparation quantum channels, and where the noise power is the lowest quantum channel.

When used to implement the ONU function, the description of other functions that can be implemented by the communication device 40 will be referred to in the embodiment shown in fig. 3, and will not be repeated.

Or, illustratively, the communication device 40 is configured to implement the functions of the OLT. The communication device 40 is for example an OLT as described in the embodiment shown in fig. 3.

The transceiver module 401 is configured to receive, by using a second optical splitter and a first optical splitter, a quantum signal from an optical network unit in a wavelength division multiplexing manner, where the quantum signal is used to indicate a first key; the transceiver module 401 is further configured to receive, by using the third optical splitter and the first optical splitter, a first encrypted signal from the optical network unit in a wavelength division multiplexing manner, or send, by using the first optical splitter and the fourth optical splitter, a second encrypted signal to the optical network unit in a time division multiplexing manner, where the first encrypted signal is obtained by encrypting a first classical signal with the first key, and the second encrypted signal is obtained by encrypting a second classical signal with the first key.

When used to implement the OLT function, reference may be made to the description of the embodiment shown in fig. 3 for other functions that can be implemented by the communication device 40, which will not be repeated.

In a simple embodiment, one skilled in the art will recognize that the communication device 40 may take the form shown in FIG. 2. For example, the processor 201 in fig. 2 may cause the communication device 40 to perform the method described in the above-described method embodiment by invoking computer-executable instructions stored in the memory 203.

Illustratively, the functions/implementations of transceiver module 401 in fig. 4 may be implemented by processor 201 in fig. 2 invoking computer-executable instructions stored in memory 203. Or the functions/implementations of the transceiver module 401 in fig. 4 may be implemented by the communication interface 204 in fig. 2.

It should be noted that one or more of the above modules or units may be implemented in software, hardware, or a combination of both. When any of the above modules or units are implemented in software, the software exists in the form of computer program instructions and is stored in a memory, a processor can be used to execute the program instructions and implement the above method flows. The processor may be built in a SoC (system on a chip) or ASIC, or may be a separate semiconductor chip. The processor may further include necessary hardware accelerators, such as field programmable gate arrays (field programmable GATE ARRAY, fpgas), plds (programmable logic devices), or logic circuits implementing dedicated logic operations, in addition to the cores for executing software instructions for operation or processing.

When the above modules or units are implemented in hardware, the hardware may be any one or any combination of a CPU, microprocessor, digital Signal Processing (DSP) chip, micro control unit (microcontroller unit, MCU), artificial intelligence processor, ASIC, soC, FPGA, PLD, special purpose digital circuitry, hardware accelerator, or non-integrated discrete devices that may run the necessary software or that do not rely on software to perform the above method flows.

Optionally, an embodiment of the present application further provides a chip system, including: at least one processor and an interface, the at least one processor being coupled with the memory through the interface, the at least one processor, when executing the computer programs or instructions in the memory, causing the method of any of the method embodiments described above to be performed. In one possible implementation, the system on a chip further includes a memory. Alternatively, the chip system may be formed by a chip, or may include a chip and other discrete devices, which are not specifically limited in this embodiment of the present application.

Optionally, an embodiment of the present application further provides a computer readable storage medium. All or part of the flow in the above method embodiments may be implemented by a computer program to instruct related hardware, where the program may be stored in the above computer readable storage medium, and when the program is executed, the program may include the flow in the above method embodiments. The computer readable storage medium may be an internal storage unit of the communication device of any of the foregoing embodiments, such as a hard disk or a memory of the communication device. The computer-readable storage medium may be an external storage device of the communication apparatus, for example, a plug-in hard disk, a smart card (SMART MEDIA CARD, SMC), a Secure Digital (SD) card, or a flash memory card (FLASH CARD) provided in the communication apparatus. Further, the computer readable storage medium may further include both an internal storage unit and an external storage device of the communication apparatus. The computer-readable storage medium is used to store the computer program and other programs and data required by the communication device. The above-described computer-readable storage medium may also be used to temporarily store data that has been output or is to be output.

Optionally, the embodiment of the application further provides a computer program product. All or part of the above-described method embodiments may be implemented by a computer program to instruct related hardware, where the program may be stored in the above-described computer program product, and the program, when executed, may include the above-described method embodiments.

Optionally, the embodiment of the application further provides a computer instruction. All or part of the flow in the above method embodiments may be implemented by computer instructions to instruct related hardware (such as a computer, a processor, an access network device, a mobility management network element, or a session management network element, etc.). The program may be stored in the above-mentioned computer readable storage medium or in the above-mentioned computer program product.

Optionally, an embodiment of the present application further provides a communication system, including: the ONU and OLT in the above embodiment.

From the foregoing description of the embodiments, it will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-described division of functional modules is illustrated, and in practical application, the above-described functional allocation may be implemented by different functional modules according to needs, i.e. the internal structure of the apparatus is divided into different functional modules to implement all or part of the functions described above.

In the several embodiments provided by the present application, it should be understood that the disclosed apparatus and method may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of the modules or units is merely a logical functional division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another apparatus, or some features may be omitted, or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and the parts displayed as units may be one physical unit or a plurality of physical units, may be located in one place, or may be distributed in a plurality of different places. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in the embodiments of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.

The foregoing is merely illustrative of specific embodiments of the present application, and the scope of the present application is not limited thereto, but any changes or substitutions within the technical scope of the present application should be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. An optical network system, the optical network system comprising: the system comprises an optical line terminal and at least two groups of optical network units, wherein the optical line terminal is provided with at least two quantum key distribution QKD receiving devices, a first receiving device, a first transmitting device and a wavelength division multiplexer, and each group of optical network units is provided with a QKD transmitting device, a second receiving device and a second transmitting device; wherein a QKD transmitting device disposed on any one group of optical network units corresponds to one QKD receiving device of the at least two QKD receiving devices, for transmitting quantum signals to the one QKD receiving device, the one QKD receiving device being configured to receive quantum signals transmitted by the QKD transmitting device disposed on the any one group of optical network units, the first transmitting device and the second transmitting device being configured to transmit classical signals, the first receiving device and the second receiving device being configured to receive classical signals;

The at least two QKD receiving devices are connected with the QKD transmitting device through the wavelength division multiplexer, the first optical splitter and the second optical splitter, the first receiving device is connected with the second transmitting device through the wavelength division multiplexer, the first optical splitter and the third optical splitter, the first transmitting device is connected with the second receiving device through the first optical splitter and the fourth optical splitter, so that the optical network unit transmits signals in a wavelength division multiplexing mode, and the optical line terminal transmits signals in a time division multiplexing mode.

2. The optical network system according to claim 1, wherein,

The QKD transmitting device comprises a transmitting unit and a first quantum key pool, wherein the transmitting unit is used for transmitting quantum signals, and the first quantum key pool is used for storing quantum keys obtained by the QKD transmitting device;

The QKD receiving device comprises a receiving unit and a second quantum key pool, wherein the receiving unit is used for receiving quantum signals, and the second quantum key pool is used for storing quantum keys received by the receiving unit.

3. An optical network system according to claim 1 or 2, wherein N second transmitting devices and M QKD transmitting devices are disposed on the at least two groups of optical network units, the N second transmitting devices corresponding to N classical channels, the M QKD transmitting devices corresponding to M quantum channels, the frequencies of the N classical channels being inversely related to the transmit powers of the N second transmitting devices, any two of the N classical channels including R preliminary quantum channels between classical channels adjacent in the frequency domain, the frequencies of the M quantum channels being included in the frequencies of (N-1) R preliminary quantum channels.

4. The optical network system according to claim 3, wherein the M quantum channels are (N-1) or (R) prepared quantum channels having the lowest noise power.

5. A method of quantum key distribution QKD in combination with an optical access network, for use in an optical network unit, the method comprising:

Transmitting a quantum signal to an optical line terminal in a wavelength division multiplexing mode through a second optical splitter and a first optical splitter, wherein the quantum signal is used for indicating a first key;

And transmitting a first encrypted signal to the optical line terminal by adopting a wavelength division multiplexing mode through a third optical splitter and the first optical splitter, or receiving a second encrypted signal from the optical line terminal by adopting a time division multiplexing mode through the first optical splitter and the fourth optical splitter, wherein the first encrypted signal is obtained by encrypting a first classical signal through a first key, and the second encrypted signal is obtained by encrypting a second classical signal through the first key.

6. The method of claim 5, wherein P second transmitting devices and 1 QKD transmitting device are disposed on the optical network unit, the P second transmitting devices corresponding to P classical channels, the 1 QKD transmitting device corresponding to 1 quantum channel, the frequencies of the P classical channels inversely related to the transmit power of the P second transmitting devices, any two of the P classical channels including R preparation quantum channels between adjacent classical channels in the frequency domain, the quantum channels being (P-1) R preparation quantum channels, the quantum channel having the lowest noise power.

7. A communication device, the communication device comprising: a transceiver module;

the optical line terminal is provided with at least two quantum key distribution QKD receiving devices, a first receiving device, a first transmitting device and a wavelength division multiplexer, and each group of optical network units is provided with a QKD transmitting device, a second receiving device and a second transmitting device;

When the communication device is used for realizing the ONU function, the receiving and transmitting module is used for transmitting a quantum signal to the optical line terminal in a wavelength division multiplexing mode through the second optical splitter and the first optical splitter, and the quantum signal is used for indicating the first key; the transceiver module is further configured to send a first encrypted signal to the optical line terminal through a third optical splitter and the first optical splitter in a wavelength division multiplexing manner, or receive a second encrypted signal from the optical line terminal through the first optical splitter and the fourth optical splitter in a time division multiplexing manner;

When the communication device is used for realizing the OLT function, the transceiver module is used for receiving a quantum signal from the optical network unit in a wavelength division multiplexing mode through the second optical splitter and the first optical splitter, and the quantum signal is used for indicating a first key; the transceiver module is further configured to receive, by using the third optical splitter and the first optical splitter, a first encrypted signal from the optical network unit in a wavelength division multiplexing manner, or send, by using the first optical splitter and the fourth optical splitter, a second encrypted signal to the optical network unit in a time division multiplexing manner.

8. The communication apparatus according to claim 7, wherein P second transmission apparatuses and 1 QKD transmission apparatus are disposed on the communication apparatus, the P second transmission apparatuses corresponding to P classical channels, the 1 QKD transmission apparatus corresponding to 1 quantum channel, the frequencies of the P classical channels inversely related to the transmission powers of the P second transmission apparatuses, any two of the P classical channels including R preliminary quantum channels between classical channels adjacent in a frequency domain, the quantum channels being quantum channels having the lowest noise power among (P-1) R preliminary quantum channels.

9. A communication device comprising a processor and interface circuitry for receiving signals from other communication devices than the communication device and transmitting signals from the processor to the processor or sending signals from the processor to other communication devices than the communication device, the processor being configured to implement the method of any one of claims 5 to 6 by logic circuitry or executing code instructions.

10. A computer readable storage medium, characterized in that the storage medium has stored therein a computer program or instructions which, when executed by a communication device, implement the method of any of claims 5 to 6.